The common method of presentation of intracranial aneurysms is at the time of their rupture (with subarachnoid haemorrhage) or on the occasion of their compression of neighbouring structures. While giant aneurysms may occasionally present with subarachnoid haemorrhage, their more common methods of presentation are due to their space occupying and neighbourhood effects22.
Giant aneurysms are commonly defined as those with a diameter larger than 2.5cm. Previously this diameter was assessed either by arteriography, so that size meant internal diameter, or by the displacement of surrounding structures, as for example, small perforating vessels, which could be attributed positively to the presence of a larger mass. Before CT scanning however, the factor of a very considerable larger aneurysm, partly occluded by clot could occasionally cause unexpected operative difficulty. The advent of CT scan and now especially MR imaging has made the prediction of the size of the aneurysm much easier and the extent of the intraaneurysmal clot also clearly definable. This paper describes one surgeon's experience with 64 giant cerebral aneurysms operated on in the last 10 years (Table 1). It has emerged from this experience that the most satisfactory method of handling the lesion is to remove the intra-aneurysmal clot and clip the neck of the aneurysm, and the steps necessary to secure this laudable design form the burden of the paper.